From: Gabriel de Perthuis <g2p.code@gmail.com>
Date: Mon, 30 Nov 2015 02:40:23 +0000 (-0800)
Subject: bcache: allows use of register in udev to avoid "device_busy" error.
X-Git-Tag: v3.16.35~625
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=6468bfb9bcd2db7697612afc854132b7554fb465;p=thirdparty%2Fkernel%2Fstable.git

bcache: allows use of register in udev to avoid "device_busy" error.

commit d7076f21629f8f329bca4a44dc408d94670f49e2 upstream.

Allows to use register, not register_quiet in udev to avoid "device_busy" error.
The initial patch proposed at https://lkml.org/lkml/2013/8/26/549 by Gabriel de Perthuis
<g2p.code@gmail.com> does not unlock the mutex and hangs the kernel.

See http://thread.gmane.org/gmane.linux.kernel.bcache.devel/2594 for the discussion.

Cc: Denis Bychkov <manover@gmail.com>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Eric Wheeler <bcache@linux.ewheeler.net>
Cc: Gabriel de Perthuis <g2p.code@gmail.com>

Signed-off-by: Jens Axboe <axboe@fb.com>
[ luis: backported to 3.16: adjusted context ]
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
---

diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index 04506f7189e71..72e660cafadde 100644
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -1954,6 +1954,8 @@ static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
 				err = "device already registered";
 			else
 				err = "device busy";
+			if (attr == &ksysfs_register_quiet)
+				goto out;
 		}
 		goto err;
 	}
@@ -1992,8 +1994,7 @@ out:
 err_close:
 	blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
 err:
-	if (attr != &ksysfs_register_quiet)
-		pr_info("error opening %s: %s", path, err);
+	pr_info("error opening %s: %s", path, err);
 	ret = -EINVAL;
 	goto out;
 }